Southern California -- this just in

Sage Stallone death remains a mystery; toxicology tests ordered

An autopsy on Sage Stallone, the oldest son of actor Sylvester Stallone, has been completed, but officials said it could take some time before an official cause of death is determined.

The L.A. County Coroner's office said it was awaiting the results of toxicology tests before completing its case.

Sage Stallone's housekeeper found the 36-year-old's body at his Studio City home on Friday. Officials said there were no signs of foul play and they didn't find a suicide note, but a security hold had been placed on the case.

The autopsy was completed Sunday morning, said Lt. Cheryl MacWillie of the coroner's office.

The oldest child of Sylvester Stallone with actress Sasha Czack, the younger Stallone began his acting career at age 14 as Rocky Balboa Jr. in "Rocky V," the 1990 installment of his father's "Rocky" movie franchise. Sage Stallone would go on to appear in 10 other movies and short films, most recently in a 2011 television documentary on the "Rocky" series.

He also worked as a director and screenwriter, and co-founded Grindhouse Releasing.

"Sage was a very talented and wonderful young man," said Sylvester Stallone's publicist, Michelle Bega. "His loss will be felt forever."

The elder Stallone, 66, was said to be "devastated and grief-stricken" by his son's death.

Sage Stallone's lawyer, George Braunstein, said his client wasn't depressed and was planning to get married.

"He had his whole life ahead of him," Braunstein said.

Sage Stallone, who had no children, was briefly married to Starlin Wright in a union annulled in 2008. His younger brother, Seargeoh, is 33.